The
following is an excerpt from Methods
in Plant Histology,
a science book that was published in the early 1900s. The book
contains various kinds of research techniques and methodology
regarding plant histology, or the study of the tissue structure
of plants. Some of the information and terminology in the
excerpt may be outdated.

The hay
infusion method

The hay infusion is a time-honoured
method for securing bacteria for study. Pour hot water on a
handful of hay, and filter the fluid through blotting paper. Place
the fluid in a glass dish, and cover with a piece of glass to keep
out the dust. When the fluid begins to appear turbid, bacteria
will be abundant. The active movements are easily observed in a
mount from the turbid water. As the bacteria pass into the resting
condition, they form a scum on the surface of the water. Usually,
the first to appear is a somewhat rod-shaped form, the Bacterium
term of the older texts. Spirillum and Coccus forms often appear
later.